Concentration of ores



' Patented May 6;, 1924.

. Miran-STA ES, PATENT! orricn.

HENRY LIVINGSTONE- SULMAN, OF LON IPON, AND EDWIN EDSEE,. OF BROCKLEY, LON- DON, ENGLAND, ASSIGNO'RS TO MINERALS SEPARATION NORTH' PORATION, OF YORK, N. Y. A CORPORATION OF MARYLAND.

CONCENTRATION OF ORES.

No Drawing; Continuation of; application Serial No. 162,320,.fi1ed April 16,. 1917. This application filed December 28, 1920.

I To aZZ whom z't' may coneexrm- Be it known that we, HENRY Lrvmcs'ronn SULMAN- and EDWIN Ensnn, subjects of the King of England, and residents, respectivel of London, England, and Brockley,

Lon on, England, have invented certain new i and useful Improvements in the Concentration of Ores, of which the following is a specification.

This invention is for improvements in or relating to the concentration of ores and it refers more particularly to flotation separation, such as by the froth-flotation process described for example in the prior United States Patent Nos. 835,120 of November 6,

1906, 962,678 ofJune 28, 1910 and 1,064,723 of June 17, 1913. This application is a continuation of our application No. 162,320 filed April 1 1917.

The f'Uth-flotation process of concentrat- 'ing ores as described in these prior specifications consists in agitating and/or aerating the crushed ore in water to which is added a minute proportion of a mineral-frothing 2 agent, for the formation of a froth of metal-liferous particles which is allowed to flo t to the surface of the liquid separate from he gangue particles, whence it is removed.

Hitherto difliculties have been experienced in the treatment of certain ores by the frothflotation process, and particularly in the recovery of oxidized metal particles such as oxides, carbonates,- etc., though it has been 5 proposed to coat such oxidized metalliferous particleswith a sulphide and thereafter to separate them from the gangue particles by flotation.

The present invention provides a means 4 whereby such hitherto experienced difiiculties may be overcome, and oxidized metalliferous particles may be floated by the froth-flotation process without any such preliminary treatment.

for the separation of certain particles from other particles in a material containing them in which the finely ground material is mixed with water to which is added a mineral- 50. frothing agent and then aerated for the formation of a froth, which is separated, there is used as the mineral-frothing agent a small quantity of one or more soluble soaps, such employed for bringing about a separation .Amongst the substances which have been a substance as silicic acid sol. I In certa n cases the separat on may be'1m- I According to this inventlonina process AMERICAN con Serial No. 432,829.

as; sodium oleate, sodium stearate, sodium palmitate, or sodium resi'nate.

The amount of fatty acid soap employed is such thatin addition to the insoluble metallie or earthy soaps'which may be formed, there must remain in the pulp, at the period of aeration, a small quantity of free, i. e. soluble, soap, but this must be less than the quantity which prgduces only a soap-airwater froth free from mineral contents.

It has now been found that soap; if used in the correct proportions, may be successfully of certain particles from other particles in a mixture containing them. In'certain cases of metalli'ferous ores treated by the process according to the present invention, the metalliferous particles are floated in preference to the gangue particles, and in other cases gangue particles maybe floated in preference to the metalliferous particles, the resultdepending on the nature of the ore and on the particular soap and the quantity employed. The circuit should beneutral or slightly alkaline in, order to avoid undue decomposition of the soap.

In some instances both the gangne particles and the metalliferous particles tend to be floated together in the froth, and in such cases substances can be added to the pulpliquor which improve both the recovery and the concentration of the mineral in' the froth, and which do not decompose the soap. Such substances are designated in the following claims as selectivity-modifying agents.

found useful for this purpose are certain oils, such as kerosen oil, gasolium oil (a hydrocarbon oil known in the trade as a. gas oil), or other hydrocarbon oils, or certain soluble salts of alkaline reaction, such as sodium silicate or sodium phosphate, or such proved by adding to the pulpfa small quantity of a caustic alkali, such as caustic soda.

The conditionsfor any. particular ore or mixture of materialsijjmaybe readily determined by experiment. Sub-aeration, such as is described for example in the prior British Patent No. 16141 7 of 1913 gives good results with the present mventio One method of carrying this invention into effect will now be described.

400gramm'es of an oxidized copper ore, from Alderley Edge, Cheshire, England, as saying 5.7% of copper of which 2770 was in the form ofcarbonate and silicate of cop per and 1.45% in the form of sulphide of copper (chalcocite) was ground to pass a 100 mesh screen and then mixed with 1600 cos. of. soft. water. The gangue was mainly quartzite. To this was added: 50 cos; of silicic acid sol containing 0.36% of silica in the form of SiO,, amounting to 0.9 lbs. per ton of ore;

2 lbs. of commercial sodium oleate per ton of ore in the form of a 5% solution;

- cuced in many cases,

2. 1 lbs; of sodiuin resinate per ton of ore in the form of an 8% solution,and

0.48 lbiof kerosene oil per ton of ore.

The pulp was a itated for one minute and the froth which formed was removed. This froth weighed 56 grammes and assayed 26.4% of copper. Two more froths were formed and removed without any further addition of reagents; together these weighed 30 grammes and assayed 11.2% of copper. The tailing's weighed 310 grammes and assayed 1.5% of copper. The recovery made by the three froths was 7 9.65% of the total copper contents of the ore.

The amount of soap employed in the example described above is not to be taken as indicating the uired in all cases.

proportion of soap .The amount can be rebut may vary from 0.01% to 1% on the ore. A preliminary trial will give the desired indication as to the quantity most suitable for treating any articular ore. In several instances we have een able to obtain successful results with a quantity of soap equivalent to 2 to 3 lbs. per ton of ore treated.

It is found that the addition of a small quantity of sodium silicate. reduces the amount of soap necessary for the formation of a froth. and it particularly advantageous in preventing the inclusion in the froth of gangue when the latter is ferruginous, in which case it floats more readily than if uncontaminated. 7

The amount of the substance such asl erosene oil, sodium silicate or sodium phosphate, which will prevent the floatation of the gangne is usually in the neighborhood of 1.0% or less on the ore. The most suitable quantity of this substanceand of the soap may be easily found by experiment.

If desired, the ore may be made into a thick pulp with the soap solution before it is finally diluted to the requisite consistency. i

The water employed in carrying the pramessinto effect should preferably be free from calcium or other salts which decompose soap.

the SiO suds or froth. "that sueh soaps can froth mg agents to produce a mineral-bcarlng In certain cases it may to add to the circuit liquors of a mineral-frothing agent a small quantity together with e o p- I It is to understood that the present invention is equally applicable to the concentration of sulphide ores-and also to the separation of'materials such as'sulphur or carbonaceous particles from otherparticles, for the separation of hornblende from felspar and quartz, or for the separation of haematite from quartz. v p

In the following claims the term tivity-niodifying agent clude such substances added to the pul for selecas are commonly the purpose of increasing or modi ying the selective action 7 of the frothing agent; Selectivity-modifying agents which have beenemployed or proposed include among other materials, sodium carbonate, sodium silicate and caustic alkalies, such as sodium hydroxide.

An example of the use of the present invention for the concentration of a sulphide ore. is as follows:

1200 grammes of an ore from the Braden copper mine in Chili containing 1.7% of topper as sulphide (chalcopyrite) in a gang-n0 consisting mainly of felspar were crushed to pass through mesh. 5000 grammes of tap water were agitated in a single cell circulating flotation machine with enough caustic soda to give a very feeble alkaline reaction. The ore was then introduced; sodium silicate at the rate of 5 lbs. per ton of ore, and sodium resinate at the rate of 0.25 lbs. per ton of ore, were added and the mixture agitated for the formation of a froth of the metalliferous particles. The froth removed during a ten minutes run was found .to weigh grammes and to assay 17. 1%

of copper, and the tailings assayed 0.42% of copper giving a recovery of 77.4%.

It has of course been heretofore generally understood that the soluble soaps which we employ would produce an air-water soap but it is our own discovery be employed as-mineralfroth in an ore pulp.'and in. our appended claims the words mineral-frothing agent designate this :mineraLbe-aring attribute of the soaps which we employ of our invention.

The term floatation agent as used in the following claims-is intended to describe such a substance as caustic soda. sodium silicate, sodium phosphate or silicic acid sol as well as an oil, whether a mineralfrothing oil or a mineral-non-frothing oil.

IV hat we claim as our invention and dc sire to secure by Letters Patent.- is:

1. The process of froth-flotation separation of oxidized metalliferous materials be advantageous is intended to 111-;

in the practiceliferous materials inafroth, aerating said mixture to form a-froth carrying the said oxidized metalliferous materlals, and re moving said froth.

2. The froth-flotation process of separat ing oxidized metalliferous particles from commingled material which consists in mixing the same with water and with a mixture of soluble soaps including a fatty-acid soap as a mineral-frothing agent in such pro or-- tions as tofloat the said-oxidized metalllferous particles in a froth, aeratin said mixture to form a froth carrying said oxidized metalliferous particles, and removing said froth. g 3. The process of froth-flotationseparation of oxidized metalliferous materials which consists in mixing a material con- ,taining the same in a finely ground condition withswater and with a mixture of solublensoaps including a fatty-acid soap as a mineral-frothing agent in such pro ortions as to float the said oxidized meta iferous materials in a froth, introducing a selectiv ity-modifying a ent' in a proportion tending to increase t e selectivlty of such flotation by the soluble soap, aerating said mixture to form a froth carrying said oxidized metalliferous materials and removing said fI'Oth. I J

l. The process offroth-flotation se aration which consists in mixing the nely ground material to be treated with'water and with a soluble soap as a frothing agent in such proportion as to float a concentrated portion of said material in a froth, intro.- ducing a modicum} of a caustic alkali and an alkaline'silicate in a pro ortion tending to increase the selectivity '0? such flotation by the soluble soap, aerating said mixture to form a froth carrying said concentrated poritlilon of said materials and removing said 5. The froth-flotation process of separating oxidized metalliferous particles from commingled material which consists-in mix ing the same with water and with a soluble fatty acid soap as a mineral-frothing agent in such proportions, as to float the said oxidized metalliferous particles in a froth, introducing a selectivity-modifying agent in a proportion tending to increase the selectivity of such by the soluble soap,'aerating, said mixture to form a flotation froth carrying' said oxidized metalliferous particles, and removing said froth.

6. The froth-flotation process of separating oxidized metalliferous particles from commingled material which consists in mix-- ing the same with water and with a soluble fatty-acid soap as a mineralfrothing agentin such pro ortions as to float the said oxidized metal iferous particles in a froth, in-

troducing a modicumgof a caustic alkali in a,' roportion tending ,to increase the selectivity of such flotation by the soluble soap, aerating said mixture to form a froth carrying said oxidized metalliferous particles, and removing said froth. 1

7. A process of froth-flotation"separation which consists in mixing with a ulp of finely round mixed materiala solu le fatty-aci 50a in less-proportion than the quantitylwiich produces onlyv a soapywater-aii' non-selective froth, agitating and aerating to roduc' separatlng t e fro h. I,

8. A process of froth-flotation separation which consists in mixing with a finely ground mixed material a otation agent includin soluble fatty-acid soap and substantially ependent on the presence of said soluble soap for froth producing qualitis, the proportion of soluble soap being such that the soluble soap present during froth formation is less than the quantity which produces only a soapy-water-air nonselective froth, agitatin and aerating to produce a selective frot and separating the froth. p

9. A process of froth-flotation separation which consists in mixing with a pulp' of finely ground mixed material a caustic alkali and a flotation agent including soluble fatty-acid soap and substantially dependent on the presence of said soluble fatty-acid soap for froth producing qualulp of 4 ities, the proportion of soluble soap being such that the soluble soap present during froth formation is less than the quantity which produces only a soapy-water-air'nonselective froth, .agltatin produce a selective 1051, the froth.

10. A process. of froth-flotation separation which consists in mixing with a pulp of finely ground mixed material a caustic alkali and a flotation a ent including a soluble'fatty-acid soap and an oil and substan tially dependent on the resence of said sol-s uble soap for. froth ro ucing qualities, the proportion of solub e soap being such that the soluble soa mation is less than the quantity which produces only a soapy-water-airhon-selective froth, agitating and aerating to produce a and separating selective froth, and se' arating the froth.

and aerating to present during froth for- 80 a selective froth, and 1 i which consists in mixing with a pulp of a finely ground mixed material having a tendency to form insolublesoap in the presence of soapy material, a quantity of soluble soapy fatty-acid material suflicient to keep some soluble soap present during froth formation in addition to any insoluble soap produced by action of soapy material on the material treated, the proportion of soapy material being such that the soluble soap present during froth formation is less than the quantity which produces only a soapy-water-air non-selective froth, agitating and aerating to produce a selective froth, and separating the froth.

14. A process ,of froth-flotation separation which consists in mixing with a pulp of a finely ground mixed material having a tendency to form insoluble soap in the presence of soluble fatty-acid soap and resinate, a flotation agent including soluble fatty acid' soap and a soluble resinate and substantially dependent on the presence of the soap and resinate for froth producing qualities, the proportion of soap and resinate being sufficient to keep some soluble soap or resinate present during froth formation in addition to any insoluble soap roduced by action of soap or resinate on t e material treated, the proportion of soap and resinate being such that the soluble soa and resinate present during froth formation is less than the quantity which produces only a soapy-waterair non-selective froth, agitating and aerat-. ing to produce a selective froth, and separating the froth.

15. {Aprocess of froth-flotation separation which consists in mixing with a pulp of a finely'ground mixed material having a tendency to form insoluble soap in the presence. of soluble soap, a flotation agent including soluble-fatty-acid soap and alkaline material andsubstantially dependent on the presence of the fatty-acid soap for froth roducing qualities, the proportion of solule soap being suflicient to keep some soluble soa'p present during froth formation in addition to any "insoluble soap produced by action 'of soapy material on the material treated, the proportion also being such that the soluble soap present during froth formation is less than the quantity which produces only a soapy-water-air non-selective froth, agitating and aerating to produce a selective froth, and separating the froth.

16. A process of froth-flotation separation avhich consists in mixing with a pulp of a finely ground material having a tendency to form insoluble soap in the presence of soluble soap a flotation agent including soluble fatty-acid soap and substantially dependent on' the presence ofsaid soluble fatty-acid soap for froth producing qualities, the proportion of soluble soap being sufficient to keep some soluble soap present during froth formation in addition to any insoluble soap produced by action of soap on the material treated, the proportion also being such that the soluble soap present during froth formation is less than; the quantity which produces only a soapy-Waterair non-selectiae froth, agitating and aerating to produce a selective froth, and separating the froth.

17. A process of froth-flotation separation which consists in mixing .with a pulp of a finely ground material having a tendency to form insoluble soap in the presence of soluble soap, :1 flotation agent including soluble fatty-acid soap and a caustic alkali and substantially dependent on the presence of the fatty-acid soap for froth producing qualities, the proportion of soluble soap being suflicient to keep some soluble soap present during froth formation in addition to any insoluble soap produced by action of soapy material on the material treated, the proportion also being such that the soluble soap present during froth formation is less than the quantity which produces only a soapy-Watcr-air non-selective froth, agitating and aerating to producea selective froth, and separating the froth.

. 18. A process of froth-flotation separation which consists in mixing with a pulp of a finely ground material having a tendency to-fo'rm insoluble soap'in the presence of soluble soap a flotation agent including a.

soluble oleate and substantially dependent on the presence of said soluble oleate for froth producing qualities, the proportion of soluble soap being sufficient to keep some soluble oleate present during froth formation'in addition to any insoluble oleate pro-. duced by action of oleate on the material.

treated, the proportion also being such that the soluble oleate present during froth formation is-less than the quantity which produces only a soapy-water-ai-r non-selective froth, agitating and aerating to produce a selective froth, and separating the froth.

' In testimony whereof, we have affixed our signatures-to this specification.

HENRY LIVINGSTONE SULMAN. EDWIN EDSER. 

